how to diagnose a misfire code P0302 in my Honda Civic 11th Generation (2022-Present)

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 2 using a socket set.
• Remove the spark plug using a spark plug socket and inspect it for wear or damage.
• If the spark plug is fouled or worn, replace it with a new one, ensuring it is gapped correctly according to specifications (typically 0.044 inches for Honda engines).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test and Replace Ignition Coil (if necessary)

• If the spark plug replacement does not resolve the issue, test the ignition coil with a multimeter to check for proper resistance.
• If the coil is faulty, remove it and replace it with a new one, ensuring it is securely connected.

4. Inspect and Replace Fuel Injector

• If the ignition components are functional, proceed to inspect the fuel injector for cylinder 2.
• Remove the fuel rail (ensure to relieve fuel pressure first) and inspect the injector for clogs or leaks.
• If the injector is defective, replace it with a new one and reassemble the fuel rail.

5. Perform Compression Test

• If misfire persists, perform a compression test on cylinder 2.
• Remove the spark plug and install the compression tester.
• Crank the engine and record the compression reading; compare it against the manufacturer's specifications.
• If compression is low, further diagnostics may be needed to identify internal engine issues.